Clean up codebase: remove unused demos and test files

- Remove dan-eden-portfolio and devigo-web demo sites
- Clean up demo testing infrastructure and scripts
- Remove frontend test files (html-preservation, style-detection tests)
- Update configuration and auth improvements
- Simplify demo structure to focus on core functionality

This cleanup reduces repository size and focuses on essential demos.

internal/auth/auth.go

@@ -25,20 +25,15 @@ type UserInfo struct {
 	Provider string `json:"iss,omitempty"`
 }
 
-// Type aliases for backward compatibility
-type AuthConfig = config.AuthConfig
-type OAuthConfig = config.OAuthConfig
-type OIDCConfig = config.OIDCConfig
-
 // AuthService handles authentication operations
 type AuthService struct {
-	config   *AuthConfig
+	config   *config.AuthConfig
 	provider *oidc.Provider
 	oauth2   *oauth2.Config
 }
 
 // NewAuthService creates a new authentication service
-func NewAuthService(config *AuthConfig) (*AuthService, error) {
+func NewAuthService(config *config.AuthConfig) (*AuthService, error) {
 	service := &AuthService{config: config}
 
 	// Initialize OIDC provider if configured
@@ -176,7 +171,7 @@ func (a *AuthService) parseOIDCToken(tokenString string) (*UserInfo, error) {
 // parseHMACToken parses and validates a JWT token using HMAC signing
 func (a *AuthService) parseHMACToken(tokenString string) (*UserInfo, error) {
 	// Parse the token
-	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (interface{}, error) {
+	token, err := jwt.Parse(tokenString, func(token *jwt.Token) (any, error) {
 		// Validate signing method
 		if _, ok := token.Method.(*jwt.SigningMethodHMAC); !ok {
 			return nil, fmt.Errorf("unexpected signing method: %v", token.Header["alg"])
@@ -336,7 +331,7 @@ func (a *AuthService) RequireAuth(next http.Handler) http.Handler {
 func (a *AuthService) HandleOAuthLogin(w http.ResponseWriter, r *http.Request) {
 	// Handle mock authentication in dev mode
 	if a.config.DevMode && a.config.Provider == "mock" {
-		response := map[string]interface{}{
+		response := map[string]any{
 			"message":      "Mock OAuth login",
 			"redirect_url": "/auth/callback?code=mock_code&state=mock_state",
 			"dev_mode":     true,